“We simply had to reduce the weight,” explains Kenneth H Svinth, CEO at Eltronic Heavy Industries, describing the problem and its solution. The lifting yoke is used for installing individual blades on offshore wind turbines, and Eltronic’s customer – a major offshore wind turbine producer – wished to switch to using a faster and smaller crane for the task,
Eltronic therefore contacted Fiberline Composites to discuss a solution using GRP profiles, which in direct comparison with steel weighs only about 25%.
“It was an essential requirement that the new GRP construction should be every bit as safe to work with as the steel original. Much of the manual work takes place at a height of eight metres, and Eltronic guarantees that the turbine blades, which are 75 metres long and weigh 25 tonnes, can be lifted into place in wind speeds as high as 14 m/s. “We found that GRP is just as reliable a material as steel,” says Svinth, referring to the extensive documentation which exists for profiles and gratings from Fiberline.
Another aspect, which although not a direct requirement from Eltronic has subsequently proved to be a major advantage, is the durability of GRP. “Visually, steel degrades rapidly in the harsh offshore environment,” says Svinth, “but this is not the case with GRP composite, which looks the same whether it has been at sea for two days or two years.”
To date, Fiberline says the collaboration has resulted in five GRP platforms. Eltronic’s platform measures 15 x 6m, weighs a total of 3 tonnes and incorporates 205m of GRP profiles and 107 m2 of GRP gratings.
It has become known recently that the US Department of Energy allocated $1.8 million to do research and develop new methods of production, transport and installation of wind turbine blades.